Which sense is the first to develop in humans?

Explanation

Olfaction or sense of smell is the human's detection of volatile chemicals in the air. The olfactory cells cover 2.5 cm in each nose half. Altogether, a human has around 20 million olfactory cells. The sense of smell is the first to be developed in a fetus. A dog's sense of smell is 100,000-1 million times more developed than that of a human being.